/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraComponent.h
Sets the delta value which is used when seeking from the current age, to the desired age. This is only relevant when using the DesiredAge age update mode.
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintCallable, Category=Niagara, Meta=(DisplayName="Set Desired Age Seek Delta")) void SetSeekDelta ( float InSeekDelta )